Wireless communication devices transmit and receive information wirelessly via a wireless access node to communicate over a communication network. Typically, the wireless access node is part of a radio access network (RAN) which provides the wireless communication devices with access to further communication networks, systems, and devices. The wireless communication devices utilize forward link communication channels to receive voice and/or data transmitted from the wireless access node, and reverse link communication channels to transmit information up to the node. Most wireless access nodes are capable of serving a large number of wireless communication devices at the same time. However, as the number of wireless devices served by a particular wireless access node increases, one or more of the wireless devices may be forced to hand down to a different wireless access network when the node becomes overloaded.
To effectuate a handoff, a wireless communication device typically utilizes a neighbor list that is provided by its serving wireless access node. The neighbor list includes an identification of pilot signals that are continuously transmitted by surrounding wireless access nodes and enables the wireless communication device to acquire the timing of a forward link channel and to compare the signal strength between nodes for determining when to handoff. The pilots are typically divided into an active set, candidate set, neighbor set, and remaining set, which are used by the wireless communication device to search for pilot signals during a handoff.
Overview
A method of operating a wireless access node to add different channel pseudo-noise (PN) codes of different carriers to a neighbor list for a wireless communication device communicating over a first carrier frequency provided by the wireless access node is disclosed. The method comprises comparing a strength of a pilot signal of an active set to a pilot threshold. The method further comprises, when the strength of the pilot signal of the active set falls below the pilot threshold, comparing first communication loading on a second carrier frequency of the wireless access node to a first loading threshold. The method further comprises starting a loading timer if the first communication loading on the second carrier frequency of the wireless access node falls below the first loading threshold. The method further comprises, during the loading timer, comparing second communication loading on hand down carriers of a highest priority neighbor to a second loading threshold. The method further comprises, if the second communication loading on at least one of the hand down carriers of the highest priority neighbor falls below the second loading threshold during the loading timer, then adding a different channel PN code of the second carrier frequency of the wireless access node to the neighbor list for the wireless communication device. The method further comprises transmitting the neighbor list having the different channel PN code of the second carrier frequency for delivery to the wireless communication device.
A wireless access node to add different channel pseudo-noise (PN) codes of different carriers to a neighbor list for a wireless communication device communicating over a first carrier frequency provided by the wireless access node comprises a processing system and a wireless communication transceiver. The processing system comprising circuitry configured to compare a strength of a pilot signal of an active set to a pilot threshold, and when the strength of the pilot signal of the active set falls below the pilot threshold, compare first communication loading on a second carrier frequency of the wireless access node to a first loading threshold. The processing system is further configured to start a loading timer if the first communication loading on the second carrier frequency of the wireless access node falls below the first loading threshold, and during the loading timer, compare second communication loading on hand down carriers of a highest priority neighbor to a second loading threshold. The processing system is further configured to, if the second communication loading on at least one of the hand down carriers of the highest priority neighbor falls below the second loading threshold during the loading timer, add a different channel PN code of the second carrier frequency of the wireless access node to the neighbor list for the wireless communication device. The wireless communication transceiver is configured to transmit the neighbor list having the different channel PN code of the second carrier frequency for delivery to the wireless communication device.
A computer apparatus to add different channel pseudo-noise (PN) codes of different carriers to a neighbor list for a wireless communication device communicating over a first carrier frequency provided by a wireless access node is disclosed. The computer apparatus comprises software instructions and at least one non-transitory computer-readable storage medium storing the software instructions. The software instructions are configured, when executed by a the wireless access node, to direct the wireless access node to compare a strength of a pilot signal of an active set to a pilot threshold, and when the strength of the pilot signal of the active set falls below the pilot threshold, compare first communication loading on a second carrier frequency of the wireless access node to a first loading threshold. The software instructions are further configured to direct the wireless access node to start a loading timer if the first communication loading on the second carrier frequency of the wireless access node falls below the first loading threshold, and during the loading timer, compare second communication loading on hand down carriers of a highest priority neighbor to a second loading threshold. The software instructions are further configured to direct the wireless access node to, if the second communication loading on at least one of the hand down carriers of the highest priority neighbor falls below the second loading threshold during the loading timer, add a different channel PN code of the second carrier frequency of the wireless access node to the neighbor list for the wireless communication device. The software instructions are further configured to direct the wireless access node to transmit the neighbor list having the different channel PN code of the second carrier frequency for delivery to the wireless communication device.